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Abstract:

An image search system includes: a storage that stores a plurality of
images; a first identification unit that identifies a deteriorated status
of a key image used for a search; and a search processing unit that
searches the images stored in the storage for a target image
corresponding to the key image while referring to a deteriorated status
of the key image identified by the first identification unit, and
comparing the key image with the images stored in the storage.

Claims:

1. An image search system comprising:a storage that stores a plurality of
images;a first identification unit that identifies a deteriorated status
of a key image used for a search; anda search processing unit that
searches the images stored in the storage for a target image
corresponding to the key image while referring to a deteriorated status
of the key image identified by the first identification unit, and
comparing the key image with the images stored in the storage.

2. An image search apparatus comprising:a first identification unit that
identifies a deteriorated status of a key image used for a search; anda
search processing unit that searches a plurality of images stored in a
storage for a target image corresponding to the key image while referring
to a deteriorated status of the key image identified by the first
identification unit, and comparing the key image with images stored in
the storage.

3. The image search apparatus as claimed in claim 2, further comprising:a
second identification unit that identifies a time-transient status of a
key image that is output to an output medium,whereinthe search process
unit narrows down the range of the images used for comparison by limiting
the number of the images stored in the storage while referring to the
time-transient status identified by the second identification unit.

4. The image search apparatus as claimed in claim 2, further comprising:a
restoration unit that restores an image that is less deteriorated by
correcting a deterioration of the key image based on the deteriorated
status of the key image identified by the first identification
unit,whereinthe search processing unit compares, with the images stored
in the storage, the image that is restored by the restoration unit based
on the key image.

5. The image search apparatus as claimed in claim 2,whereinthe search
processing unit directly compares the key image with images stored in the
storage while referring to the deteriorated status of the key image
identified by the first identification unit.

6. The image search apparatus as claimed in claim 2, further comprising:a
deterioration unit that, based on the deteriorated status of the key
image identified by the first identification unit, deteriorates images
that are stored in the storage that are being used for comparison, so
that quality of the images nears that of the key image,whereinthe search
processing unit compares the key image with the images stored in the
storage, the images being deteriorated by the deterioration unit.

7. The image search apparatus as claimed in claim 2, further comprising:a
first restoration unit that, based on the deteriorated status of the key
image identified by the first identification unit, corrects deterioration
of the key image, and restores an image that is less deteriorated; anda
second restoration unit that, based on the deteriorated statuses of the
images that are stored in the storage that are being used for comparison,
corrects the deterioration of the images being used for comparison, and
restores images that are less deteriorated,whereinthe search processing
unit compares, with the restored images of the images used for
comparisons by the second restoration unit, the image that is restored
for the key image by the first restoration unit.

8. The image search apparatus as claimed in claim 2,whereinthe first
identification unit comprises:a deteriorated status estimation unit that
performs a data analysis of the key image to estimate the deteriorated
status of the key image.

9. The image search apparatus as claimed in claim 2, further comprising:a
time-transient status acceptance unit that accepts a user instruction to
designate a time-transient status for a key image that is output to an
output medium,whereinthe first identification unit comprises:a
deteriorated status estimation unit that estimates the state of the
deterioration of the key image based on the time-transient status of the
key image received by the time-transient status acceptance unit.

10. The image search apparatus as claimed in claim 2,whereinthe first
identification unit comprises:an acceptance unit that accepts a user
instruction for designating at least one location on the key image where
deterioration occurs, a deterioration type and a deterioration degree;
andan estimation unit that employs a predetermined method for estimating
a location on the key image where deterioration occurs, a deterioration
type and a deterioration degree that is not designated by a user
instruction.

11. The image search apparatus as claimed in claim 3, further comprising:a
time-transient estimation unit that performs a data analysis to prepare a
time-transient status estimation for the key image.

12. The image search apparatus as claimed in claim 3,whereinthe
time-transient estimation unit comprises:a time-transient status
acceptance unit that accepts a user instruction to designate a
time-transient status for the key image that is output on an output
medium.

13. An image search system comprising:a storage that stores a plurality of
images;a first identification unit that identifies a time-transient
status of a key image, that is output on a output medium; anda search
processing unit that, while referring to the time-transient status of the
key image identified by the first identification unit, narrows down a
range of the images stored in the storage to obtain a reduced number of
images, and compares the reduced number of images with the key image, so
that all the images stored in the storage are searched for a targeted
image corresponding to the key image.

14. An image search apparatus comprising:a first identification unit that
identifies a time-transient status of a key image, that is output on a
output medium; anda search processing unit that, while referring to the
time-transient status of the key image identified by the first
identification unit, narrows down a range of the images stored in a
storage storing a plurality of images to obtain a reduced number of
images, and that searches all the images stored in the storage for a
targeted image corresponding to the key image by comparing the reduced
number of images with the key image.

15. A computer readable medium storing a program causing a computer to
execute a process for performing a search process during which stored
images are searched for a target image, the process comprising:accepting
a designation of a key image used for a search;identifying a deteriorated
status of the key image accepted by the key image acceptance unit;
andsearching all the stored images for a target image that corresponds to
the key image by referring to the deteriorated status identified of the
key image and comparing the key image with stored images.

16. A computer readable medium storing a program causing a computer to
execute a process for performing a search process during which stored
images are searched for a target image, the process comprising:accepting
a designation of a key image to be used for a search;identifying a
time-transient status of the key image, accepted by the key image
acceptance unit, following output of the key image on an output
medium;performing a process, for all stored images by referring to the
time-transient status identified, that sets and applies a selection
qualifier satisfied by the statuses of a reduced number of images;
andsearching all the stored images for a target image that corresponds to
the key image by referring to the time-transient status identified of the
key image, narrowing down a range of the stored images to obtain a
reduced number of images, and comparing the reduced number of images with
the key image.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application is based on and claims priority under 35 U.S.C. 119
from Japanese Patent Application No. 2007-329699 filed Dec. 21, 2007.

BACKGROUND

[0002]1. Technical Field

[0003]The present invention relates to an image search system, an image
search program for searching for a desired image among a plurality of
registered images (stored images), and a computer readable medium.

[0004]2. Related Art

[0005]Search systems are employed in a number of fields, to search for
desired images, such as ones that are identical to, or similar to,
designated key images, by scanning multiple images that are stored on
portable storage media, such as CD-ROMs, DVD-ROMs or memory cards, or on
large capacity storage media, such as hard disks or optical disks.

SUMMARY

[0006]According to a first aspect of the present invention, an image
search system includes: a storage that stores a plurality of images; a
first identification unit that identifies a deteriorated status of a key
image used for a search; and a search processing unit that searches the
images stored in the storage for a target image corresponding to the key
image while referring to a deteriorated status of the key image
identified by the first identification unit, and comparing the key image
with the images stored in the storage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]Exemplary embodiment of the present invention will be described in
detail based on the following figures, wherein:

[0008]FIG. 1 is a diagram illustrating an example configuration for a
document processing, history management system that includes an image
search system according to a first embodiment of the present invention;

[0009]FIG. 2 is a diagram illustrating a first example arrangement for the
document processing, history management apparatus;

[0010]FIG. 3 is a diagram illustrating a second example arrangement for
the document processing, history management apparatus;

[0011]FIG. 4 is a diagram illustrating a third example arrangement for the
document processing, history management apparatus;

[0012]FIG. 5 is a diagram illustrating a fourth example arrangement for
the document processing, history management apparatus;

[0013]FIG. 6 is a diagram for explaining a difference in search methods
employed by the search processors of image search apparatuses in the
first to the fourth example arrangements;

[0014]FIG. 7 is a diagram illustrating a fifth example arrangement for the
document processing, history management apparatus;

[0015]FIG. 8 is a diagram illustrating a sixth example arrangement for the
document processing, history management apparatus;

[0016]FIG. 9 is a diagram illustrating a seventh example arrangement for
the document processing, history management apparatus;

[0017]FIG. 10 is a diagram illustrating an eighth example arrangement for
the document processing, history management apparatus;

[0018]FIG. 11 is a diagram for explaining example pairs obtained using
search methods (1) to (4) and additional functions (a) to (c);

[0019]FIGS. 12A and 12B are diagrams for explaining the feature of the
search process performed by the document process history management
apparatus 6 (specifically, the image search apparatus 7) of the first
embodiment; and

[0020]FIG. 13 is a diagram illustrating an example configuration for an
image search system according to a second embodiment of the present
invention.

DETAILED DESCRIPTION

[0021]The embodiments of the present invention will now be described in
detail while referring to drawings.

System Configuration

First Embodiment

[0022]FIG. 1 is a diagram of an example configuration for a document
processing history management system wherein an image search system,
according to a first embodiment of the present invention, is
incorporated. As illustrated in FIG. 1, a document processing, history
management system 1 is constituted by: various imaging apparatuses 3 (3A
to 3E), each of which has an included image output function, for
outputting an image to be reproduced on a printing medium, such as paper,
and an included image acquisition function, for reading an image from a
printing medium, for example, and obtaining digital data; a process
instruction apparatus 4, such as a personal computer, for transmitting
image acquisition or output instructions to the imaging apparatuses 3;
and a document processing, history management apparatus 6, which has a
server function, for recording, saving, managing and searching for
document images, and a history function, for preparing processing
histories (also termed logs), together with statuses, for document images
for which acquisition and output processes are performed by the various
imaging apparatuses 3. The imaging apparatuses 3, the process instruction
apparatus 4 and the document processing, history management apparatus 6
are connected by a network 9, which is an example communication means.

[0023]The document processing, history management system 1 includes: an
image search system 2 according to the first embodiment; and a storage
section that, when various process operations are performed for a
document, stores in or on a predetermined storage medium an operation
history that includes an image corresponding to the document that is
processed and information designating the corresponding operating status.

[0024]The imaging apparatuses 3 are, for example: a copier 3A, which has
an image acquisition function and an image output function (collectively
called a copying function); a printing apparatus 3B, which is called a
printer and which has only a single function (a printing function, an
example image output function); an image reading apparatus 3C, which is
called a scanner and which has an image acquisition function
(specifically called a scanner function); a multifunctional apparatus 3D,
which has a printing function, a copying function and a scanner function;
and a facsimile machine 3E. The apparatuses 3A to 3E are connected to the
document processing, history management apparatus 6 via the network 9 or
other predetermined connection interfaces. In FIG. 1, only one imaging
apparatus 3 is provided for each type; however, an arbitrary number of
apparatuses may be employed, and not all the types may be provided for
use.

[0025]Assuming that the copier 3A is connected to the document processing,
history management apparatus 6 via the network 9, when, for example, a
user enters a copy instruction by manipulating the console panel (not
shown) of the copier 3A, the copier 3A reads an image (specifically,
reads digital data for the image; this also applies to the following
explanation) in accordance with the copy instruction, and transmits the
image data, via the network 9, to the document processing, history
management apparatus 6. Prior to this, however, to authenticate the
authority of the user to enter the copy instruction, the copier 3A may
request that the user enter a valid user name and password, following
which the copier 3A may transmit to the document processing, history
management apparatus 6 not only the image data, but also other
information, such as the user name, obtained during verification of the
user.

[0026]Furthermore, the copier 3A does not directly perform a process for
reproducing on a paper sheet an image that is read, but receives from the
document processing, history management apparatus 6 image data to be used
for the image forming process, and employs the received image data to
form a corresponding image on a paper sheet. That is, the copier 3A first
transmits to the document processing, history management apparatus 6
image data obtained by reading a document to be copied, and then
continues the processing based on image data received from the document
processing, history management apparatus 6.

[0027]The printing apparatus 3B is connected to the document processing,
history management apparatus 6 via a serial bus interface, and reproduces
an image on a printing medium, such as paper, based on image data
received from the document processing, history management apparatus 6.

[0028]The image reading apparatus 3C is connected to the document
processing, history management apparatus 6 via the network 9, and when a
user enters a reading instruction by either manipulating the console
panel (not shown) of the image reading apparatus 3C or by operating the
process instruction apparatus 4, the image reading apparatus 3C reads an
image in accordance with the reading instruction, and transmits the
obtained image data to the document processing, history management
apparatus 6. At this time, to authenticate the authority of the user who
entered the reading instruction, the image reading apparatus 3C may
request that the user enter a valid user name and password, and may
thereafter transmit to the document processing, history management
apparatus 6 not only the image data but also other information, such as
the user name, that is obtained during verification of the user.

[0029]The multifunctional apparatus 3D is connected to the document
processing, history management apparatus 6 via the network 9, and
performs the same functions as of the copier 3A, the printing apparatus
3B, the image reading apparatus 3C and the facsimile machine 3E.

[0030]The facsimile machine 3E is connected to the document processing,
history management apparatus 6 via a serial bus interface. The facsimile
machine 3E transmits, via facsimile, image data obtained by scanning, or
outputs a facsimile image reproduced on an output medium, such as paper,
based on received image data, and outputs to the document processing,
history management apparatus 6 an image to be processed for transmission
or reception.

[0031]The process instruction apparatus 4 is connected to the document
processing, history management apparatus 6 via the network 9, and
transmits to the document processing, history management apparatus 6
image data for a document to be processed by the printing apparatus 3B
and the image reading apparatus 3C and associated information, such as
the name of a user who entered a process instruction.

[0032]The document processing, history management apparatus 6 includes a
server function whereby, upon receiving a request from the process
instruction apparatus 4, which is a client system, the imaging apparatus
3 is permitted to perform either the image acquisition process or the
image output process; whereby the features of a document image are
recorded or saved on a predetermined storage device in order to store, as
processing history, a processed image and associated processing
information; and whereby stored information is searched for as target
information, and the information that is obtained is presented to a user.
The same system, as well as various other well known systems, can
basically be employed for acquiring and storing processing history and
for performing a search.

[0033]The document processing, history management apparatus 6 (also an
incorporated image search apparatus 7) includes a control unit 12 and a
data holding unit 14, which serves as an image database (image DB) that
includes, as a storage device, a hard disk device or an optical disk
device for storing a processed image and a processing history in
correlation. The control unit 12 can employ the same hardware
configuration as that for a common computer that includes a CPU (Central
Processing Unit) that is a hub for the performance of a control process
and of a computation process; and memories, such as RAM (Random Access
Memory) and ROM (Read Only Memory), in which processing data and program
data are stored. Since this example configuration is a well known
configuration that is used for a computer, such as a personal computer,
constituted by a micro processor that executes predetermined processing
software, the configuration is not shown.

[0034]In this embodiment, the arrangement of the control unit 12 that
performs the main function, i.e., that performs a process for storing
image data for a document and data for operation histories in the data
holding unit 14 and for managing these data, or that performs a process
used to search through information stored in the data holding unit 14 to
find target information (e.g., an image that is identical or similar to
an image used as a search key and associated operation information), can
be provided not only by using a hardware processing circuit, but also by
software, employed by a computer, that is based on program code that
performs the above described function.

[0035]Therefore, the image search system of this invention can be provided
as a software program to be executed by a computer, or as a
computer-readable storage medium on which this program is stored. When
software is employed to perform the system, operating procedures can be
easily changed without alterations of the computer hardware being
required.

[0036]When software is to be employed to perform the functions for saving,
managing and searching for document image data and associated operation
history information, a relevant software program, recorded on a recording
medium, may be installed, for example, in a computer (a micro-computer)
system that includes incorporated special hardware, such as an SOC
(System On a Chip), for which a CPU, a logical circuit and a storage
device are mounted on a single chip to provide a desired system, or in a
general-purpose personal computer that can perform a variety of functions
when software programs for the functions are installed.

[0037]A recording medium is one for which a status change in energy, such
as magnetic, optical or electric energy, is generated in accordance with
a description supplied by a program, and using a corresponding signal
form, the description supplied by the program is transmitted to a reading
apparatus supplied as a hardware resource for a computer. An example
recording medium is one that is to be distributed to a user, and is to be
separately employed, for a computer, in order to provide a program, e.g.,
the medium can be a magnetic disk (including a flexible disk FD), an
optical disk, such as a CD-ROM (Compact Disc-Read Only Memory), a DVD
(Digital Versatile Disc) or an MO (Magneto Optical disk), or a package
medium (a portable storage medium), such as a semiconductor memory. A
recording medium can also be a ROM or a hard disk on which a program is
stored, which is provided for a user, by being incorporated in advance in
a computer. Further, a software program may be provided not only via a
recording medium, but also via a wire or wireless communication network.

[0038]The control unit 12 receives from imaging apparatuses 3, such as the
copier 3A and the printing apparatus 3B, image data to be processed and
information concerning process operations, such as the name of a user who
requested image processing, the processing date and the processing
condition, and stores, as processing history data, document image data
and associated data (e.g., a document ID, a version and an attribute) in
the data holding unit 14. In addition, the control unit 12 transmits
received image data to imaging apparatuses 3, such as the copier 3A, the
printing apparatus 3B and the facsimile machine 3E, to initiate image
processing. Further, the control unit 12 receives an instruction for a
search to be performed for processing history information, and performs
the search process, i.e., searches the data holding unit 14 for the
processing history information, and presents the search results.

[0039]In order to perform the search process, when an image is processed
by the imaging apparatuses 3, information (an identifier, an ID) that
uniquely identifies an image and a version VO are embedded in advance in
an output medium (an arbitrary medium, such as paper or a file that holds
digital data) by using means such as a barcode, an ID tag or an
electronic watermark. When the processed image is to again be processed
by the imaging apparatus 3, the ID and the version of the image are
supplied. Then, a document image G1 stored in the data holding unit 14,
which is designated based on information that is obtained, is compared
with a document image G2 that is obtained by reading the output medium (a
matching procedure).

[0040]A description, obtained for a first point of view and related to the
search process, will now be given for the main part of the control unit
12 mechanism that performs the image comparison process for this
embodiment. The deteriorated status of an input image I IN, which is a
key image for a search process, is employed as a reference, and a search
of all the images stored in the data holding unit 14 is performed for a
target image that corresponds to the key image (input image I IN). In
this manner, the search process is performed more accurately than a
search process performed for a target image by comparing the deteriorated
input image I IN with registered images I REC. That is, while taking into
consideration the deteriorated status of the input image I IN of the
document image G2, relative to the original document image, the accuracy
with which the search process is performed is the same as that when a
comparison is performed using an original document image as a key image.
The employment, from the first point of view, of the mechanism will be
described later in detail.

[0041]Further, a description, from a second point of view, will be given
later for the main part of the mechanism of the control unit 12 for this
embodiment. The control unit 12 narrows down the range of images to be
used for comparison by referring to the time-transient status of the
input image I IN, which is the key image for the search process. As a
result, the period required for the search process can be reduced,
compared with the period that would be required were the target image
search process performed by comparing the input image I IN with all the
images registered.

[0042]In a case wherein a document image G2 is a generated copy that is
obtained through repetitive duplication (copying), or has been output
(printed), on an output medium, for a considerable period of time (e.g.,
several years), it is anticipated that the image may have been
deteriorated by repetitive copying, the attachment of dust, or the
browning of ageing paper. From the second point of view, the mechanism
employed performs the search process while taking into account the fact
that when such a deteriorated image is used as a search key, it is highly
probable that the search accuracy will be reduced and the search period
will be extended.

[0043]The mechanism employed, from the first point of view, that performs
the search process by referring to the deteriorated status of the input
image I IN, which is the key image for the search, and the mechanism
employed, from the second point of view, that performs the search process
by narrowing down the range of images to be compared, while referring to
the time-transient status of the input image I IN, which is the key image
for the search, are provided from different points of view. The control
unit 12 does not necessarily employ perform two mechanisms at the same
time, and may employ either mechanism. Of course, it is preferable that
the control unit 21 employ both mechanisms.

[0044]FIG. 2 is a diagram illustrating a first example arrangement for the
document processing, history management apparatus 6. The first example
arrangement for the document processing, history management apparatus 6
includes: a first image search apparatus 7, provided for the first
example arrangement; and a functional section whereby, when various
processing operations are to be performed for a document, an image of the
document to be processed and information indicating the operating status
of the document are collectively stored, as an operation history of the
document, in the data holding unit 14.

[0045]In this instance, the control unit 12 includes, as the mechanism for
performing the above described process and more specifically as a
functional block, a document image acceptance unit 22 that receives an
processed image from a document reading unit 92 that is mounted, for
example, on the copier 3A, the image reading apparatus 3C or the
multifunctional apparatus 3D. The document image acceptance unit 22
includes a function unit for obtaining an image that is to be stored, and
to be used for image log management, and a key image acceptance unit for
receiving an instruction issued to designate a key image to be used for a
search process.

[0046]A user sets up (places), in a predetermined location on the document
reading unit 92, an original image P1, and enters an instruction 01, such
as one for the copying, the transmission by fax or the scanning of the
original image P1 or for the erasure of the original image P1 using a
shredder, in an operating unit 94 (or the process instruction apparatus
4) such as the console panel of the imaging apparatus 3. The document
reading unit then reads from the document P1, the image I IN of the
document (the original) (specifically called an input image), document
identification information (ID) D1 for uniquely specifying the document,
and version information V1 for specifying a version.

[0047]The control unit 12 also includes: an operation information
acceptance unit 24, which receives from an operating unit, such as the
console panel of the imaging apparatus 3, information concerning an
operation to be performed for a document; and an operation history
recording unit 26 that stores, in the data holding unit 14, an operation
history that includes an image received by the document image acceptance
unit 22, or an image to be stored in consonance with the document image
(which images are hereinafter collectively referred to as a registered
image I REC), and associated information specifying an operating status.
During the storage process, the registered image I REC and the associated
information (e.g., a document ID, a version and an attribute) are stored
in correlation with each other. The operation information acceptance unit
24 and the operation history recording unit 26 are functional portions
that, when various operations are performed for a document, collectively
store, as the operation history, the registered image I REC consonant
with the document to be processed and the information specifying the
operating status in the data holding unit 14.

[0048]In addition, the control unit 12 also includes, as a functional
portion related to the search control: a search processor 30, which
performs a search process by taking into consideration (referring to) the
deteriorated status of an input image I IN that is entered as a key image
for a search; and a process results information presentation unit 40,
which presents various data, based on search results obtained by the
search processor 30, to the user.

[0049]The search processor 30 of the embodiment can employ, for example,
one of the following four methods (1) to (4) to perform the search
process by awhile taking into consideration the deteriorated status of an
input image I IN that is entered as a key image for a search. For the
first example arrangement, the first method (1) is employed.

[0050](1) The input image I IN is restored, by taking image deterioration
into consideration, and the restored image R IN that is obtained is
compared with the registered image I REC.

[0051](2) Neither the input image I IN nor the registered image I REC is
processed, and during the comparison process, matching is performed by
taking image deterioration into consideration.

[0052](3) While taking image deterioration into consideration, the
registered image I REC is deteriorated to near the level of the input
image I IN, and a thus obtained deteriorated image D REC is compared with
the input image I IN.

[0053](4) In a case wherein the registered image I REC is also
deteriorated, both the input image I IN and the registered image I REC
are corrected (restored) by taking image deterioration into
consideration, and the restored images (the restored image R IN and the
restored image R REC) are then compared.

[0054]The search processor 30 of the first example arrangement employs the
first search method (1), and the following is the first main part.
Instead of employing the document image G2 as a search key image to be
directly compared with the document G1, an image for which the condition
is as near that of the original document image as possible is restored by
taking into consideration the deteriorated status of the document image
G2, relative to the original document image, and the restored image (also
referred to as the restored image R IN) is employed as a search key
image. That is, in a case wherein the input image is deteriorated, a
restored image R IN for which the condition is as near that of the
original image as possible is generated and used as a search key.

[0055]Preferably, during the image restoration process performed by taking
status deterioration into consideration, the time-transient status of the
image that is output (printed) should be employed as a reference for
specifying (estimating) the status deterioration. Further, the second
main part is that, during the image search process, the image search
range is narrowed down by referring to the time-transient status of the
image that is output (printed).

[0056]Therefore, the search processor 30 is characterized by the
designated the status deterioration for the input image I IN (either by
estimating the status deterioration, or by receiving from a user a
designated status deterioration), and by restoring an image in consonance
with the status deterioration. In addition, provided for the search
processor 30 is a functional section for performing a process for
specifying the time-transient status of an image that was output to an
output medium (or for estimating the time-transient status, or for
receiving a user designated time-transient status), for narrowing down
the range of search targets in accordance with the time-transient status,
and for comparing the restored image R IN with the registered image I
REC.

[0057]For example, the search processor 30 of the control unit 12 includes
a deteriorated/time-transient status specification unit 31 (which serves
as both a deteriorated status specification unit and a time-transient
status specification unit) that designates the deteriorated status or the
time-transient status of the input image I IN. The
deteriorated/time-transient status specification unit 31 in the first
example arrangement is characterized by estimating both the deteriorated
status and the time-transient status of the input image I IN, and also by
estimating the time-transient status of the input image I IN, based on
the deteriorated status. That is, an arrangement is employed wherein one
component serves as a deteriorated status estimation unit and a
time-transient status estimation unit.

[0058]When an image is deteriorated, it can be assumed that a
predetermined time period has elapsed since the image was output, and
when the predetermined time period has elapsed since the image was
output, it can be assumed that the image is deteriorated. A specific
correlation is established between the deteriorated status and the
time-transient status, and it can be ascertained that the level (the
degree) of a change differs, depending on an environmental condition.
Therefore, it can be assumed that the deteriorated status actually
indicates the time-transient status or conversely, it can also be assumed
that the time-transient status actually indicates the deteriorated
status. Thus, substantially, an arrangement may be used wherein a
time-transient status specification unit is excluded and only a
deteriorated status specification unit is provided, or an arrangement may
be employed wherein a deteriorated status specification unit is excluded
and only a time-transient status specification unit is provided.

[0059]Specifically, the deteriorated/time-transient status specification
unit 31 includes: a deteriorated/time-transient status estimation unit 32
(which serves as both a deteriorated status estimation unit and a
time-transient status estimation unit) that estimates the deteriorated
status of the input image I IN received by the document image acceptance
unit 22, and estimates the time-transient status based on the estimated
deteriorated status (e.g., estimates the number of years that have
elapsed since an image was output to a sheet of paper); and an image
restoration unit 34, which employs the deteriorated status estimated by
the deteriorated/time-transient status estimation unit 32, and corrects
the deterioration of the image to generate a restored image R IN for
which the condition is as near that of the original image as possible
(i.e., restores an image for which deterioration has been corrected).

[0060]The deteriorated/time-transient status estimation unit 32 estimates
the deteriorated status of the input image I IN by performing a data
analysis for the input image I IN, and also estimates and outputs the
number of elapsed years for the input image I IN. To provide an estimated
deterioration status and an estimated time-transient status, a common
method used in a photographic process can be employed. For example, the
yellowish staining of a blank space on the obverse side of a sheet or of
the blank reverse side, or the degree of ink fading (for example,
reference color data can be printed in advance in a blank space on the
obverse side, or on the blank reverse side, and can later be compared
with the condition of the ink used for an image) can be specifically
employed for an evaluation of the deteriorated status, and the
time-transient status can be estimated based on the result of the
evaluation performed for the deteriorated status.

[0061]The image restoration unit 34 restores an image in accordance with
the deteriorated status and the time-transient status that are estimated
by the deteriorated/time-transient status estimation unit 32, and outputs
a restored image R IN. For the generation of the restored image R IN, a
generally employed process for image correction (see, for example,
JP-A-2005-316743) can be performed, whereby the luminance and the colors
of the deteriorated input image I IN are corrected by referring to the
deteriorated status and the number of years that have elapsed, which are
estimated by the deteriorated/time-transient status estimation unit 32,
by improving the input image I IN until the quality is near that of an
original image that is not deteriorated.

[0062]The search processor 30 of the control unit 12 also includes a
matching unit 35 that searches data stored in the data holding unit 14,
using as a key image the restored image R IN generated by the image
restoration unit 34, to find an identical or similar image and operation
information for that image. The matching unit 35 includes: a reader 36
for reading a registered image I REC from data stored in the data holding
unit 14; and an image comparator 39, for comparing the restored image R
IN, generated by the image restoration unit 34, with registered images I
REC, read by the reader 36, and for using differences between these
images for calculating differential information, Diff(G3, IREC).

[0063]A method described, for example, in JP-A-11-212993, in JP-A-9-035058
or JP-A-2001-319232, for comparing feature values for individual images,
can be employed for image matching.

[0064]The image comparator 39 performs image matching, and provides a
search result score. The search results score is an indicator used to
represent the level (the degree) of a match obtained for two images (in
this embodiment, the restored image R IN and the registered image I REC).

[0065]At this time, in order to reduce the period required for the search
process, instead of referring to all the registered images in the data
holding unit 14, which serves as an image DB, the matching unit 35
(specifically, the image comparator 39) narrows down the target image
range, until only those registered images in the data holding unit 14 are
included for which the years elapsed satisfy the years elapsed count for
the input image I IN. Then, the matching unit 35 performs the matching
process for the thus obtained images, and outputs an example score list
that includes document IDs and differential information Diff. That is,
for the individual registered images in the image DB that are selected,
the matching unit 35 narrows down the search target range using the
number of years elapsed, and performs matching between the registered
images I REC, for which the number of years elapsed is satisfied, and the
restored image R IN. The search target range may also be narrowed down to
include images falling within a specific range extending from before to
after the elapsed years. As another method for narrowing down the search
target range, the number of years elapsed may be employed to allocate
weighted scores, e.g., the weight allocated for an image near the elapsed
years may be increased, while the weight allocated for an image farther
from the elapsed years may be reduced, and an image for which the total
score is equal to or smaller than a predetermined value may be excluded.

[0066]Furthermore, the control unit 12 includes: a data generator 44 that,
based on the restored image R IN corresponding to the input image I IN
and the document identification information D1, generates search results
and information concerning the operation history of an image that was
searched for (collectively referred to output information); and an output
unit 46 that outputs the output data generated by the data generator 44
using sheet paper, by email, or transmission to an output destination
such as a facsimile line. The data generator 44 and the output unit 46
constitute a process results, data presentation unit 40 (which serves as
a search results presentation unit and an operation history presentation
unit) that, upon receiving a search instruction, generates and presents
search results information and information related to operation histories
for documents to be searched for and other associated documents.

[0067]The output information generated by the data generator 44 is, for
example, an output image I OUT corresponding to the input image I IN,
character information corresponding to the document identification
information D1 that specifies a document, and character information that
corresponds to version information. The process results, information
presentation unit 40 receives a list consisting of pairs of document IDs
and scores from the image comparator 39, sorts the pairs in the
descending order of the scores, and outputs the paired list as the search
results.

[0068]That is, according to the image search apparatus 7 in the first
example arrangement, the deteriorated/time-transient status estimation
unit 32 estimates the number of years elapsed for the input image I IN
that is a designated key image to be used for a search, and the image
restoration unit 34 restores an image in consonance with the number of
years estimated. Then, the image comparator 39 of the search processor 30
performs matching between the input image I IN and the registered images
I REC in the data holding unit 14 for which the number of years elapsed
is satisfied, and outputs the list of document IDs and scores.
Sequentially, the process results information presentation unit 40 sorts
the pairs of document IDs and scores in the descending order of the
scores, and outputs the paired list as the search results.

[0069]For the first example arrangement shown in FIG. 2 and second to
fourth example arrangements that will be described later, modifications
for which one of three additional functions (a) to (c) is provided can be
employed (a detailed explanation will be given for fifth to eighth
example arrangements). When an additional function is provided, a
functional portion that performs the additional function should be also
added to the arrangement. Instead of adding a portion, a functional
portion in the first to fourth example arrangements may be removed.

[0070](a) The deteriorated/time-transient status estimation unit 32 is
removed, and the time-transient status entered by a user (e.g., the
number of years elapsed) is employed by the image restoration unit 34 and
the matching unit 35.

[0071](b) A matching method is employed whereby, information concerning a
portion that is drastically deteriorated or that has been missed (called
deteriorated location information) is received from a user, and a process
is performed whereby an image is divided into blocks and matching is
performed for the individual blocks.

[0072](c) A user is permitted to enter a deteriorated status (the type or
the degree of deterioration), and information concerning the type or the
deterioration level entered by the user is employed to perform an image
correction process (an image restoration or deterioration process), or a
matching process.

[0073]FIG. 3 is a diagram illustrating a second example arrangement for
the document processing, history management processing apparatus 6. Since
the document processing, history management apparatus 6 in the second
example arrangement includes the image search apparatus 7 provided for
the second example arrangement, the structure of this the image search
apparatus 7 differs from that of the included for the document
processing, history management apparatus 6 in the first example
arrangement.

[0074]The image search apparatus 7 in the second example arrangement is
characterized by employing, as a method (a search method) for performing
a search process by taking into consideration the deteriorated status of
the input image I IN that is entered as a key image to be used for a
search, the second search method (2): "Neither the input image I IN nor
the registered image I REC is processed, and during the comparison
process, matching is performed by taking image deterioration into
consideration." An obvious difference from the first example arrangement
is that the image restoration unit 34 is eliminated because the input
image I IN and the registered image I REC are not to be processed.

[0075]Further, in a process for matching the input image I IN and the
registered images I REC, the matching unit 35 (specifically, the image
comparator 39) provides a search results score while taking image
deterioration into consideration. The image deterioration is specified by
employing, as a reference, the time-transient status (e.g., the number of
years elapsed) that is estimated by the deteriorated/time-transient
status estimation unit 32. According to the second example arrangement,
the search results score is an indicator that represents the level (the
degree) of a match obtained for the input image I IN and the registered
image I REC.

[0076]FIG. 4 is a diagram illustrating a third example arrangement for the
document processing, history management processing apparatus 6. Since the
document processing, history management apparatus 6 in the third example
arrangement includes the image search apparatus 7 shown in the third
example arrangement, the structure of this image search apparatus 7
differs from that for the document processing, history management
apparatus 6 in the first example arrangement.

[0077]The image search apparatus 7 in the third example arrangement is
characterized by employing, as a method (a search method) for performing
a search process by taking into consideration the deteriorated status of
the input image I IN, which is entered as a key image to be used for a
search, the third search method (3): "While taking into consideration
image deterioration, the registered image I REC is deteriorated to near
the level of the input image I IN, and the deteriorated image D REC is
compared with the input image I IN". A first difference from the first
example configuration is that the image restoration unit 34 is removed
because the input image I IN is not to be processed. As a second
difference, the matching unit 35 includes a deterioration unit 37,
because the registered image I REC is to be deteriorated by taking image
deterioration into consideration. When the registered image I REC is read
from the data holding unit 14 by the reader 36, the deterioration unit 37
deteriorates the registered image I REC based on the time-transient
status that is estimated by the deteriorated/time-transient status
estimation unit 32, generates a deteriorated image D REC having an image
quality that is as near to that of the input image I IN as possible, and
outputs the deteriorated image D REC to the image comparator 39.

[0078]Specifically, the deterioration unit 37 intentionally changes an
image in consonance with, for example, the number of years elapsed
estimated by the deteriorated/time-transient status estimation unit 32,
so that the obtained image becomes similar to the input image I IN. Thus,
the deteriorated image D REC is output. For generation of the
deteriorated image D REC, while referring to the number of elapsed years
estimated by the deteriorated/time-transient status estimation unit 32,
image correction is performed to intentionally deteriorate the registered
image I REC whose luminance and colors are not deteriorated, so that the
registered image I REC becomes similar to the input image I IN whose
luminance and colors are deteriorated. The direction in which a
correction is performed is the reverse of that in which a correction is
performed by the image restoration unit 34; however, the basic correction
mechanism can be regarded as being the same.

[0079]The matching unit 35 (specifically, the image comparator 39)
compares the input image I IN with the deteriorated image D REC of the
registered image I REC, and provides a search result score. According to
the third example arrangement, the search result score is an indicator
that represents the level (the degree) of a match between the input image
I IN and the deteriorated image D REC.

[0080]FIG. 5 is a diagram illustrating a fourth example arrangement for
the document processing, history management processing apparatus 6. Since
the document processing, history management apparatus 6 in the fourth
example arrangement includes the image search apparatus 7 shown in the
fourth example arrangement, the structure of this image search apparatus
7 differs from that for the document processing, history management
apparatus 6 in the first example arrangement.

[0081]The image search apparatus 7 in the fourth example arrangement is
characterized by employing, as a method (a search method) for performing
a search process by taking into consideration the deteriorated status of
the input image I IN that is entered as a key image to be used for a
search, the fourth search method (4): "In a case wherein the registered
image I REC is also deteriorated, both the input image I IN and the
registered image I REC are corrected (restored) by taking image
deterioration into consideration, and the restored images (the restored
image R IN and the restored image R REC) are compared." An obvious
difference from the first example arrangement is that, in addition to the
image restoration unit 34 provided for the input image I IN, an image
restoration unit 38 is provided as a second image restoration unit. When
a registered image I REC is deteriorated, the image restoration unit 38
corrects the registered image I REC based on the deteriorated status of
the registered image I REC, and generates a restored image R REC that is
as near the original image as possible (i.e., restores an image from
which deterioration has been removed). It should be noted that, in the
fourth example arrangement, the image restoration unit 34 provided for
the input image I IN serves as the first image restoration unit.

[0082]As the deteriorated status of the registered image I REC, the number
of years elapsed for the registered image I REC is estimated and
employed. For the estimation of the number of years elapsed, a common
method used in a photographic process can be employed in the same manner
as the deteriorated/time-transient status estimation unit 32 to estimate
the status of the input image I IN. For example, the yellowish condition
of the blank space of the registered image I REC, or the degree of ink
fading (for example, reference color data is printed in advance on the
blank space and later, is to be compared with the existing condition) is
employed to estimate the number of years elapsed. The image deterioration
is also taken into consideration when the registered image I REC is
restored, so that a case wherein the registered image I REC was obtained
by reading a deteriorated image can be coped with.

[0083]The matching unit 35 (specifically, the image comparator 39)
compares the restored image R IN of the input image I IN with the
restored image R REC of the registered image I REC, and provides a search
result score. According to the fourth example arrangement, the search
result score is an indicator that represents the level (the degree) of a
match between the restored image R IN and the restored image R REC.

(Comparison of Search Methods)

[0084]FIG. 6 is a diagram for explaining a difference in the individual
search methods employed by the search processors 30 of the document
processing, history management apparatuses 6 (especially, the image
search apparatuses 7) in the first to the fourth example arrangements. A
description will be given by employing an example wherein 100 indicates
the levels of the individual R (red), G (green) and B (blue) signals at
the pixel positions where the input image I IN is located, and 120
indicates the levels of the individual R (red), G (green) and B (blue)
signals at the same pixel positions of the original image (an image of
the original before the generation copying is performed).

[0085](1) in FIG. 6 is a diagram for explaining the image correction
process for the matching process performed by the search processor 30 of
the first example arrangement. In the first example arrangement, while
taking image deterioration into consideration, the R value, the G value
and the B value of the input image I IN are corrected to R=118, G=118 and
B=118, for example, so that the R, G and B values are near those of the
original image. Then, the restored image R IN, which is obtained by
correcting the R value, G value and B value of the input image I IN, is
compared with the registered image I REC.

[0086](2) in FIG. 6 is a diagram for explaining the image correction
process for the matching process performed by the search processor 30 of
the second example arrangement. A description will be given by employing
an example wherein R=120, G=120 and B=120 are the levels of R (red), G
(green) and B (blue) signals at the pixel positions (hereinafter referred
to as a matching position) of a portion of the registered image I REC
that is to be compared and that is read by the reader 36.

[0087]According to the second example arrangement, during a comparison
process, matching is performed while taking image deterioration into
consideration and processing both the input image I IN and the registered
image I REC. For example, assume that R=100, G=100 and B=100 are for the
input image I IN in the matching position, and when R=120, G=120 and
B=120 are at the corresponding pixel positions for the registered image I
REC, read by the reader 36. In this case, to perform matching, it is
believed that the actual R, G and B values for the input image I IN are a
little greater because the input image I IN is deteriorated, or it is
believed that R=120, G=120 and B=120 for the registered image I REC, read
by the reader 36, should be decreased slightly so a comparison can be
performed with the input image I IN. Either this, or the two methods may
be employed to perform matching.

[0088](3) in FIG. 6 is a diagram for explaining the image correction
process during the matching process performed by the search processor 30
in the third example arrangement. A description will be given by
employing an example wherein R=120, G=120 and B=120 are the levels of R
(red), G (green) and B (blue) signals at matching positions for of the
registered image I REC, read by the reader 36. According to the third
example arrangement, while taking image deterioration into account, the
R, G and B values of the registered image I REC, read by the reader 36,
are intentionally reduced, for example, to R=102, G=102 and B=102, so
that the R, G and B values of the registered image I REC are near those
of the input image I IN. Then, the deteriorated image D REC, which is
obtained by lowering the R, G and B values of the registered image I REC,
is compared with the input image I IN.

[0089](4) in FIG. 6 is a diagram for explaining the image correction
process during the matching process performed by the search processor 30
in the fourth example arrangement. A description will be given by
employing an example wherein R=110, G=110 and B=110 are the levels of R
(red), G (green) and B (blue) signals at the matching positions of the
registered image I REC, read by the reader 36, and wherein R=120, B=120
and B=120 are the levels of R (red), G (green) and B (blue) signals at
the same positions of the original image (the image of the original
before generation copying is performed). According to the fourth example
arrangement, in a case wherein the registered image I REC as well as the
input image I IN is deteriorated, the R, G and B values of the registered
image I REC are also corrected, for example, to R=119, G=119 and B=119 by
taking image deterioration into consideration, so that the R, G and B
values of the registered image I REC are near those of the R, G and B
values of the original image. Then, the restored image R IN, obtained by
correcting the R, G and B values of the input image I IN, is compared
with the restored image R REC, obtained by correcting the R, G and B
values of the registered image I REC.

[0090]FIG. 7 is a diagram illustrating a fifth example arrangement for the
document processing, history management apparatus 6. The document
processing, history management apparatus 6 in the fifth example
arrangement includes an image search apparatus 7 provided for the fifth
example arrangement. The fifth example arrangement and the sixth to
eighth example arrangements, which will be described later, are
characterized in that a function (one of, or an arbitrary number of
functions from (a) to (c)) explained at the end of the first example
arrangement is additionally provided for either the first to fourth
example arrangements. The fifth example arrangement has a feature whereby
at least the first additional function (a) is employed. Referring to the
example in FIG. 7, the fifth example arrangement is illustrated by
providing only the first additional function (a) for the first example
arrangement.

[0091]As illustrated in FIG. 7, for the document processing, history
management apparatus 6 (specifically, the image search apparatus 7) of
the fifth example arrangement, first, the deteriorated/time-transient
status estimation unit 32 is eliminated from the search processor 30.
Instead, the image search apparatus 7 includes, as an example
time-transient status specification unit, the time-transient acceptance
unit 52 for receiving a time-transient status (e.g., the number of
elapsed years) designated by a user. Information that is received by the
time-transient acceptance unit 52, designating the time-transient status,
is employed by the image restoration unit 34 and the matching unit 35.
This process should be suitable for performance when a user searches for
and reprints an original image based on a deteriorated image that was
previously output by a printer. In this case, since the user knows the
number of elapsed years (and the output device that was used), the user
enters this information through the time-transient acceptance unit 52.

[0092]In order to permit the image restoration unit 34 to employ
information that indicates the time-transient status, a deteriorated
status estimation unit 32a is provided as an example deteriorated status
specification unit. The deteriorated status estimation unit 32a estimates
the deteriorated status of the input image I IN based on the
time-transient status information that is received by the time-transient
status acceptance unit 52, and the image restoration unit 34 restores the
image in accordance with the deteriorated status estimated by the
deteriorated status estimation unit 32a. The function of the deteriorated
status estimation unit 32a may be included in the image restoration unit
34. The time-transient status can actually be regarded as the
deteriorated status, and an arrangement without the deteriorated status
estimation unit 32a is also available.

[0093]A method generally employed in the photographic process can be used
for an estimation of the deteriorated status, based on the time-transient
status that is designated by a user. For example, the number of elapsed
years and the deterioration condition of an image are correlated in
advance, and the estimated number of elapsed years is employed to
estimate image deterioration (e.g., the degree of ink fading).

[0094]The image restoration unit 34 and the image comparator 39 perform
processing based on the time-transient status (the designated number of
elapsed years) that the user knows, instead of the time-transient status
(the estimated number of elapsed years) that is estimated by the
deteriorated/time-transient status estimation unit 32 in the first
example arrangement. Since image restoration and matching are performed
by referring to the designated number of elapsed years, instead of the
estimated number of elapsed years, the accuracy of the restoration of the
key image can be increased, compared with that in the first example
arrangement. In addition, the image comparator 39 can narrow down the
search target range using the number of elapsed years that is designated
in consonance with the actual situation.

[0095]It should be noted that the first example arrangement having the
additional function (a) has been employed to provide the fifth example
arrangement in FIG. 7. However, when the third example arrangement having
the function (a) is employed, time-transient status information received
by the time-transient status acceptance unit 52 can be employed by the
deterioration unit 37. And when the fourth example arrangement having the
function (a) can be employed, such information is processed by the image
restoration unit 38. In either case, the accuracy of the image correction
is improved, compared with the other example arrangements.

[0096]FIG. 8 is a diagram illustrating a sixth example arrangement for the
document processing, history management apparatus 6. The document
processing, history management apparatus 6 in the sixth example
arrangement includes an image search apparatus 7 provided for the sixth
example arrangement. The sixth example arrangement is characterized in
that a function (one of, or an arbitrary number of functions from (a) to
(c)) explained at the end of the first example arrangement is
additionally provided for either of the first to fourth example
arrangements, and is specifically characterized in that at the least the
second additional function (b) is employed. Referring to the example in
FIG. 8, the sixth example arrangement is illustrated by providing only
the second additional function (b) for the second example arrangement.

[0097]As shown in FIG. 8, the document processing, history management
apparatus 6 (specifically, the image search apparatus 7) of the fifth
example arrangement includes a deteriorated portion acceptance unit 54
that receives, from a user, information (called deteriorated portion
information) related to a drastically deteriorated portion or a missing
portion, and the deteriorated portion information received by the
deteriorated portion acceptance unit 54 is employed by the matching unit
35. This process is suitable for performance by a comparison system
whereby an image is divided into blocks and matching is performed for the
individual blocks.

[0098]For the sixth example arrangement, a deterioration status
specification unit is constituted by the deteriorated status estimation
portion of the deteriorated/time-transient status estimation unit 32 and
the deteriorated portion acceptance unit 54. Since deteriorated portion
information related to the deteriorated status of the input image I IN is
entered by a user through the deteriorated portion acceptance unit 54,
the deteriorated status estimation function of the
deteriorated/time-transient status estimation unit 32 simply estimates
the type or the degree of deterioration, rather than the deteriorated
portion.

[0099]Further, the image comparator 39, for example, omits (skips) score
calculation for a block that corresponds to information (deteriorated
portion information), entered by a user, that indicates a drastically
deteriorated portion or a missing portion. Therefore, compared with the
second example arrangement, the search accuracy is improved and the
search process period is shortened.

[0100]It should be noted that the second example arrangement having the
function (b) has been employed to provide the sixth example arrangement.
However, when the first example arrangement having the function (b) is
employed, deteriorated portion information received by the deteriorated
portion acceptance unit 54 can be employed by the image restoration unit
34. And when the third example arrangement having the function (b) is
employed, such information can be employed by the deterioration unit 37.
Further, when the fourth example arrangement having the function (b) is
employed, the information can be employed by the image restoration unit
38. And in any case, the accuracy of the image correction is improved,
compared with the other example arrangements.

[0101]For example, when the first example arrangement having the function
(b) is employed, the image restoration unit 34 varies a correction level
for an individual block, i.e., increases the correction level for a block
that corresponds to information (deteriorated portion information),
entered by a user, that indicates a drastically deteriorated portion or a
missing portion. Also for the other example arrangements, the image
restoration unit 34 varies a correction level for an individual block,
and employs a correction level, differing from those of the other
portions, to correct an indicated block in the deteriorated portion
information.

[0102]FIG. 9 is a diagram illustrating a seventh example arrangement for
the document processing, history management apparatus 6. The document
processing, history management apparatus 6 in the seventh example
arrangement includes an image search apparatus 7 provided for the seventh
example arrangement. The seventh example arrangement is characterized in
that a function (one of, or an arbitrary number of functions from (a) to
(c)) explained at the end of the first example arrangement is
additionally provided for either the first to fourth example
arrangements, and is specifically characterized in that at the least the
third additional function (c) is employed. Referring to the example in
FIG. 9, the seventh example arrangement is illustrated by providing only
the third additional function (c) for the first example arrangement.

[0103]As illustrated in FIG. 9, the document processing, history
management apparatus 6 (especially, the image search apparatus 7) of the
seventh example arrangement includes: a deterioration type/level
acceptance unit 56, which receives a deterioration condition
(specifically, the type and the level of deterioration) from a user.
Information concerning the deterioration type and level, received by the
deterioration type/level acceptance unit 56, is employed by the image
restoration unit 34 and the matching unit 35. This process is suitable
for performance when a user employs input information for the
deterioration type and level to perform a correction (or a restoration in
the first example arrangement having the function (c)) or a comparison of
images.

[0104]In the seventh example arrangement, the deteriorated status
specification unit is constituted by the deteriorated status estimation
function of the deteriorated/time-transient status estimation unit 32 and
the deterioration type/level acceptance unit 56. Since the deterioration
type and level information related to the deteriorated status of the
input image I IN is designated by the user through the deterioration
type/level acceptance unit 56, the deteriorated status estimation
function of the deteriorated/time-transient estimation unit 32 simply
performs an estimation for a deteriorated portion, rather than the
deterioration type or level that is entered by the user.

[0105]The image restoration unit 34 performs image restoration using
information, entered by a user, that indicates a deterioration type
(e.g., the deterioration of colors, the lack of colors, the deterioration
of edges or the damage caused by noise) and a deterioration level. As a
result, compared with the first example arrangement, the accuracy with
which a key image is restored is increased.

[0106]Further, the image comparator 39 performs image matching using the
information, entered by the user, that indicates a deterioration type
(e.g., the deterioration of colors, the lack of colors, the deterioration
of edges or the damage caused by noise) and a deterioration level. As a
result, compared with the first example arrangement, the search accuracy
is improved, and the search process period is reduced.

[0107]It should be noted that the first example arrangement having the
function (c) has been employed to provide the seventh example
arrangement. However, when the third example arrangement having the
function (c) is employed, deteriorated status information received by the
deteriorated type/level acceptance unit 56 can be employed by the
deterioration unit 37. When the fourth example arrangement having the
function (c) is employed, such information can be employed by the image
restoration unit 38. In either case, the accuracy with which the image
correction is performed is improved, compared with the other example
arrangements.

[0108]FIG. 10 is a diagram illustrating an eighth example arrangement for
the document processing, history management apparatus 6. The document
processing, history management apparatus 6 in the eighth example
arrangement includes an image search apparatus 7 provided for the eighth
example arrangement. The eighth example arrangement is characterized in
that a function (one of, or an arbitrary number of functions from (a) to
(c) explained at the end of the first example arrangement is additionally
provided for either the first to fourth example arrangements. Referring
to the example in FIG. 10, the eighth example arrangement is illustrated
by providing all of the first to third additional functions (a) to (c)
for the second example arrangement. As is apparent from FIG. 10, this
arrangement is so designed that the fifth, sixth and seventh example
arrangements are assembled with the second example arrangement. For the
eighth example arrangement, the time-transient status acceptance unit 52
serves as an example time-transient status specification unit, and the
deteriorated portion acceptance unit 54 and the deterioration type/level
acceptance unit 56 constitute a deteriorated status specification unit.

(Example Pairs of Search Methods and Additional Functions)

[0109]FIG. 11 is a diagram for explaining example pairs obtained through
the four types of search methods (1) to (4) described in the first to
fourth example arrangements, and the three additional functions (a) to
(c) described in the fifth to seventh example arrangements. The eighth
example arrangement illustrated in FIG. 11 has been provided by employing
the first example configuration having all the first to the third
additional functions (a) to (c). However, an arbitrary set can be
employed, and as shown in FIG. 11, various arrangements can be obtained.

[0110]In FIG. 11, "◯" indicates specifically an especially
effective pair, and "Δ" indicates an available pair, although not
as effective as a pair indicated by "◯".

(Example Search Operation)

[0111]FIGS. 12A and 12B are diagram for explaining the feature of the
search processing performed by the document processing, history
management apparatus 6 (specifically, the image search apparatus 7) of
this embodiment. FIG. 12A is a diagram illustrating an example search
operation performed according to a comparison example, and FIG. 12B is a
diagram illustrating an example search operation performed by the image
search apparatus 7 of the first example arrangement according to this
embodiment.

[0112]During the search processing performed in the comparison example, as
shown in FIG. 12A, an input image I IN is compared with registered images
I REC. At this time, when the input image I IN is obtained by reading a
generation copy that is formed by repetitive duplication (copying), or
when the input image I IN has been output (printed) on an output medium
for a considerable period of time (e.g., several years), the image might
be deteriorated due to the repetitive copying, or by the attachment of
dust or growing a yellowish staining of a sheet.

[0113]When the deteriorated input image I IN is directly compared with the
registered images I REC, the search accuracy is reduced. Further, when
the entire registered images, i.e., all the registered images I REC
stored in the data holding unit 14, are employed as search targets to be
compared with the input image I IN, a long period is required for the
search.

[0114]On the other hand, for the search processing of this embodiment, as
shown in FIG. 12B, the deteriorated/time-transient status estimation unit
32 estimates the number of elapsed years based on the deteriorated input
image I IN that is the search key image, the image restoration unit 34
restores the image by referring to the estimated number of elapsed years,
and the matching unit 35 performs matching using the restored image R IN.
Since the restored image R IN, for which the deterioration has been
corrected, is employed for matching, the search accuracy is increased,
compared with the comparison example that directly compares the
deteriorated input image I IN with the registered images I REC.

[0115]In addition, while referring to the number of elapsed years
estimated by the deteriorated/time-transient status estimation unit 32,
the matching unit 35 narrows down the search target range for images, and
compares these images with the restored image R IN. Since the number of
search target images becomes smaller than the total number of registered
images I REC stored in the data holding unit 14, the search process
period is shorter than the comparison example that employs all the
registered images for comparison.

System Configuration

Second Embodiment

[0116]FIG. 13 is a diagram illustrating an example configuration for an
image search system according to a second embodiment of the present
invention. As shown in FIG. 13, an image search system 2 for the second
embodiment is separated from the document processing, history management
apparatus 6, and is appropriate for a system that mainly performs an
image search operation. The image search system 2 can be applied for a
case wherein, for example, a standalone computer 8 is employed as an
image search apparatus 7 and multiple registered images that the computer
8 can handle are to be searched to find a desired image.

[0117]The first to the eighth example arrangements described in the first
embodiment or the other example arrangements shown in FIG. 10 can be
employed for the functional arrangement of the image search apparatus 7
for the second embodiment.

[0118]Registered images used as search targets can, for example, be images
to be stored in a storage device (not shown) incorporated in the computer
8, images recorded on a portable storage medium 82, such as a flexible
disk FD, a CD-ROM, a DVD-ROM or in semiconductor memories having various
specifications (in FIG. 13, semiconductor memories 1 to 4 of four
different types), or images stored in an electronic apparatus 84 (an
external storage device 84a or a semiconductor memory mounted on a
digital camera 84b) that is connected to the computer 8 by employing a
predetermined method (e.g., a USB (Universal Serial Bus)).

[0119]The image search apparatus 7 of the image search system 2, as well
as in the first embodiment, includes a control unit 12. The control unit
12 can employ the same hardware configuration as that for a common
computer that includes a CPU, which is a hub for performing a control
process and a computation process; and memories, such as RAM and ROM, in
which process data and program data are stored. Since this example
hardware configuration is well known as the configuration of a computer,
such as a personal computer, constituted by a micro processor that
executes predetermined processing software, the configuration is not
shown.

[0120]In the second embodiment, the arrangement of the control unit 12
that performs the main function, i.e., that performs a search process to
find a target image (e.g., an image identical or similar to a search key
image) in image data stored in a predetermined storage medium, can be
provided not only using a hardware processing circuit, but also by
software provided using a computer based on program code that performs
the above described function.

[0121]The foregoing description of the embodiments of the present
invention has been provided for the purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed. Obviously, many modifications
and variations will be apparent to practitioners skilled in the art. The
embodiments were chosen and described in order to best explain the
principles of the invention and its practical applications, thereby
enabling others skilled in the art to understand the invention for
various embodiments and with the various modifications as are suited to
the particular use contemplated. It is intended that the scope of the
invention defined by the following claims and their equivalents.